1. Field of the Invention
The present invention relates to a process for preparing a mixture of potassium monopersulfate, potassium bisulfate, and optionally, potassium sulfate by partial neutralization of Caro's acid (H.sub.2 SO.sub.5) with a basic potassium compound and crystallization.
2. Prior Art
U.S. Pat. No. 2,901,319 discloses reacting a mixture of H.sub.2 SO.sub.5 :H.sub.2 SO.sub.4 in a mole ratio of 2 to 10:1 with K.sub.2 CO.sub.3, KHCO.sub.3 or KOH using a mole ratio K.sup.+ :H.sub.2 SO.sub.5 of from 0.6-1.2 at a temperature of from -10.degree. to 40.degree. C. The product is washed with ethanol and dried using a vacuum.
U.S. Pat. No. 3,036,885 discloses reacting hydrogen peroxide, potassium peroxydisulfate and fuming sulfuric acid cooling the reaction mixture, bringing the pH to 1-2 with an alkali and evaporating moisture from the resulting salts until they are dry.
U.S. Pat. No. 3,041,139 discloses neutralizing a mixture of H.sub.2 SO.sub.5 and H.sub.2 SO.sub.4 with a basic potassium compound to form an aqueous solution which on drying will contain the triple salt KHSO.sub.4.K.sub.2 SO.sub.4.2KHSO.sub.5.
British Pat. No. 979,450 discloses reacting hydrogen peroxide with concentrated sulfuric acid or oleum to form a monopersulfuric acid solution, adding potassium bisulfate or potassium sulfate to the monopersulfuric acid solution, neutralizing the resulting solution with a solution of a basic potassium compound and air drying the neutralized solution.
Canadian Pat. No. 575,441 discloses treating dried potassium monopersulfate containing mixtures with magnesium carbonate.